1. Field of the Invention
This invention relates to an information processing method and apparatus and a providing medium. More particularly, it relates to an information a processing method and apparatus and a providing medium in which, if the hair is to be represented by a curve, the end of the hair is mixed with the background to permit the hair end to be seen to have a fine size.
2. Description of the Related Art
For representing the human hair in the conventionally computer graphics, there are used a method of approximating the hair in its entirety using a polygonal model and bonding the texture of the hair on its surface, as shown in FIG. 1A, and a method of effecting lettering using an anisotropic reflection model exhibiting differential reflection intensity depending on different light source positions or different viewing point positions. These methods are described in Yamana and Suenaga, xe2x80x9cHair Representation Using Anisotropic Reflection Modelxe2x80x9d SHIN-GAKU GIHOU, PRU87-3, pp. 115 to 120, 1989.
However, with the above-mentioned method of approximating the hair style using the polygon model, it is difficult to represent a complex hair pattern, such as triple knitting hair pattern, or to represent hair movement.
As a method for modelling individual hairs, there are proposed a method of approximating a hair by a polygon model of a triangular pyramidal shape, and a method of approximating a sole hair by the combination of a large number of shorter line segments. These methods are described in K. Anjo, Y. Usami and T. Kurihara, xe2x80x9cA Simple Method for Extraction of the Natural Beauty of Hairxe2x80x9d, Computer Graphics, vol. 26, pp. 111-1120, 1992.
However, the method of representing the sole hair using a polygon model of a triangular pyramidal shape is in need of voluminous data, while the fair thickness is increased to give an unnatural appearance. Moreover, with the method of approximating a sole hair using the combination of a large number of line segments, it is difficult to interconnect the numerous line segments smoothly.
As a method of overcoming the above-mentioned difficulties, there is proposed a method of specifying plural control points p1 to p7 and to generate parametric curves, such as Bezier curves or B-spline curves, from the coordinates of the control points, to approximate the hair. This method is disclosed in Kobayashi, Morishima and Harashima, xe2x80x9cMotion Model of a Filamentary Body and CG Simulationxe2x80x9d SHIN-GAKU GIHOU, PRU90-127, pp. 15 to 20, 1991.
However, the method of generating the Bezier curves or the B-spline curves for approximating the hair has a drawback that, since the hair thickness is perpetually constant from the root to the hair end, the massy feeling of the hair is lowered at the hair end.
It is therefore an object of the present invention to suppress the lowering of the massy feeling of the end of the hair by mixing the luminance value of the hair end with the luminance value of the background to permit the hair end to be seen as being of reduced thickness.
In one aspect, the present invention provides a information processing apparatus for drawing a filamentary object including means for storing a plurality of control points, means for generating a line from the control points stored in the storage means, means for specifying a portion of the line generated by the generating means, means for computing luminance values of the line portion specified by the specifying means and means for synthesizing luminance values of the line portion computed by the computing means and luminance values of the background.
In another aspect, the present invention provides an information processing method for drawing a filamentary object including a step for generating a line from a plurality of control points, a step for specifying a portion of the line generated by the generating step, a step for computing luminance values of the line portion specified by the specifying step and a step for synthesizing luminance values of the line portion computed by the computing step and luminance values of the background.
In yet another aspect, the present invention provides a providing medium for providing to an information processing apparatus for drawing a filamentary object a program designed to permit execution of processing including a step for generating a line from a plurality of control points, a step for specifying a portion of the line generated by the generating step, a step for computing luminance values of the line portion specified by the specifying step, and a step for synthesizing luminance values of the line portion computed by the computing step and luminance values of the background.